Process of concentrating nitric acid.



- F. 'HAUSMANN PROCESS OF GONGENTRATING- NITRIC ACID.

APPLIGATION FILED SEPT.9,1913.

Patented Get.

great attention so AIL-AA. a

FRITZ HAUSMANN, GE MANNHEIILVI, GERMANY, ASSiG'NQIt TO THE FIRM OF VEREIN' CHEMISCHER FiLBR-IKEN IN MANNHEIM,

OF IJIANIZIHEIM, GERTJATANY.

PROCESS OF CONCENTBATING ISIIEIRIC- ACID.

Patented out. 2-7, on.

1 5,15 1 2 Specification of Letters KPaten/z.

Application filed September 9, 1812. Serial No. 788,89".

To (171 Il /1077b it may concern:

,e it known that 1, liRlTZ HAUsMAnN, engineer, a subject of the King of Prussia and the German Emperor, residing at Kiiferthalerstrassc 2&6, Mannheim, Grand ,Duchy of Baden, German Empire, have invented a new and useful Improvement in Processes of Concentrating Nitric Acid; and

I do hereby declare the following to be a full, clear. and exact description of the same.

lligh percentage nitric acid or nitric acid inmiohydrate is in considerable demand for many manufacturing purposes and in order to meet this demand, a mixture of sulfuric acid and nitric acid has been introduced in a definite quantity into a distilling vessel and distilled under a high vacuum. as in the l alcutiner process which does not operate in a continuous manner and yields a nitric acid containing at most from 96 to 98 per cent. llhlf), with a content of 0.5 per cent. and more of N 0,, and a considerable amount of eal; acid. Owing to this process not be lug ((MtlHHOUS, it ne ifessitates a heavy consumption of coal and great car of the apparatus and the use of a high vacuum makes the ap 'iaratus complicated and requires that the cost of manufacture by such process is very high.

I have fourul that from a mixture of sulfuric acid and nitric acid, highly concentrated nitric acid and nitric acid monohydrate can be manufactured almost free from impurities in a continuous manner and with out the use of a high vacuum.

Accifu'dingz to this invention the mixture of acids is led through the distilling apparatus in a thin layer ontinuously moving,' forward hile at the same time air (or equivalent gas f) is passed through the ap 'iaratus in tie-n toward the outlet for the of nitric a d, so that the air, or gas, niiXture carries off with it the vapors The air, or fl'aS, or gas mixpreferably previously dried. 'ihtpath which the mixture of acids takes through the :qiparatus, made as long practicable.

The Way in Which the invention can be 1 performed will be readily understood from i i g l l l l l l l the following" denwriptiou with reference to l the accmnpanyino; drawing which shows an apparatus suitalivlc for carrying out the invention, but the invention is not limited to the use ot the precise form of apparatus illustrated.

in the drawing Figure 1 shows a vertical I section and Fig. 2 a plan of an apparatus" suitable for carrying out the process.

.lhe still is as low as possible and 1s preferablydish shaped so that only the bottom 0. requires to be heated. The cover I) rests in air, or any suitable cooling means, such, for instance, as cold gases. This cooling favors the retaining of any vapors of suln=eely in place and is cooled by the surround furic acid, so that the nitric acid obtained is,v

iree from sulfuric acid. acids is preferably introduced through the com ral tube j and the residual acid passes off by the outlet pipe g. The supply is so f- The mixture. of H fected that the mixture of acids is freed much as possible from nitric acid when it leaves the apparatus. The inlet is preferl')l arranged at the part of the path which is most distant from the outlet, so that the mixture has to run over the longest path be.

fore it reaches the outlet. The depth of the layer of liquid is preferably maintained at not more than from 30 to 40 millimeters so that a saving of fuel will be obtained, owing to no unnecessarily high column or depth of liquid (about 1000 millimeters in Valentiners process) having: to be heated. Aprolonged path of the mixture of acids through the apparatus is formed by guiding; channels it. The pipes (Z supply air or other gas, or gas mixture, to the. apliiaratus. The cover ,7) is preferably provided with a depending; lllll ivhich is peripherally adjusted to as shown in the drawing and which extends dovvn to the level of the liquid, or dips a lit tie into it. ii the arrangement of the rim 1 the supply of air, or the like takes place as uniformly as possible and, passing over the surface of the liquid, carries aiv v with. it the nitric acid vapors and at the same time cools the liquid, thereby accelerating the distilling.- operation. preventing decompositions of the nitric acid and favoring the recondensaiiion of sulfuric acid. The air. or the like. and nitric acid vapors are led away through the tube (1 and the nitric acid vapors are condensed in any suitable comic-user.

In comparison with the processes Working with a vacuum, the condensing devices are I, l-in 'devicesand towers. a I 'fihe draft required in the apparatus can lie producedby a chimney, suction fans atthe'e'nd of the condensing device;

i -cloul1 e' .thatof an-ap I a. vacuum and of equal bottom area, and even five times as much as in aforesaid apheating greatly siinplified and may consist, foriristance,- of refrigerating orms with collector by regulatable Afcii'cular shape is mostconvenient 'for the distillation vessel, but-:other, forms such be used v at The yield of this apparatus is more than aratus operating with 10 for example as polygonal, or-elliptical, rnay paratuses'comparin g the total heating area.

In addition 'to very highly concentrated acid or inonohydrate' only a small part of weak acid "is vobtained-and this being per- 20 feetly'free from N O can be maintained at a concentration of to per cent. HNO The advantages of .the process according to this invention are that. acid of concentration up to inonohydrate is obtained, that the is continuous and that in contradistinction to. the intermittent Working, the temperature can be maintained uniform both in the still and in the condensation and collecting device. By this nieans the 1 heat is very eificicntly'utilizcd and conseacid monohydrate fr and lower. OXKlS otnitr in heating a mixture of pa-ratus, moying the heated 'inirrtnre hori-' z-ontally inra GOHtll'lHOllSiStIBfiHl forward through the I distillation apparatus While cold gases not passed over the surface. otthe heated mix decomposingnitric' acid' are ture, and leading the fumes of'nitric acid maining sulfuric acid.

2. The process of manufacturing Very:

highly concentrated nitric acid upto mono? nitrous acid and hydrate and free, from loiver oxide of nitrogen" which consists in heating a mixture ofsul'furic acid and nitric 'acld'in one thln layer in.

a distillation apparatus, moving the heated mixture horizontally in a continuous str-eainforward through the distillation apparatus While cold air is passed over the surface of the heatedfiinixtnre and 'lea'dingthe fumes of nitric acid with air out of contact with the remaining sulfuric a'cid.

3. The process of be from nitrous acid. .gcn which consists sulfuric acid and inanu'tacturin g 1 n itric with the gases out of contact with the .re-

nitric acid in one thin layer in a distillation" apparatus moving the heated mixture-hold zontally in a continuous strewn-forward through the distillation apparatus Wh11e coldwair previously dried'is passed over'the' surface of the heated mixture andleachng;

the fumes of nitric acid with air out of con.- tact with the reinainmg sulfuric acid, In testimony whereof, I have signed my two subscribing ii'itnesses."

' l lfiilfj HAUSMANN Witnesses JOSEPH Prnirrnn, -H'nmnrcn REIGER,

name to this specification in thc'presence-ofi 

